use your hulu app
Yes you can sideload movies you already own on disk after converting them using a program like dvd catayst and your pc. You can rent or purchase tv shows and movies for direct download from BN, it takes quite a while. There have been some problems with ultra violet but using flixter many of these can be streamed. These are large files so you may want to add a sd card if keeping them on the device for very long.
Ginger-Maci, there is something called Nook Videos.
If you press the physical N button below the screen of your HD+, you'll be taken to your Home Screen.
At the bottom are 6 buttons. One of them says 'Shop'. Just press that.
On the Shop Main Page, at the top right will be a list of 'Things you can buy'. It's like a list of buttons. One of them will say 'Movies & TV Shows'. Tap that.
Now you will be shown a list of movies and TV Shows available to rent and buy from Nook.
Your other options are:
Crackle (a free app with a range of free movies and shows)
Buying from else where and sideloading to Nook using a program like the one DVD Catalyst makes for Nook.
etc. - like what other responders have replied.